A tilted parallel plate in converging light is useful as a beamsplitter to form two separate images. However, whereas with such a tilted plate the reflected image is perfect, the transmitted image may contain spherical aberration, coma, astigmatism and in chromatic light longitudinal and lateral color.
In the past these problems have been found to be correctable. However, past methods of correction have employed highly complicated and costly lens systems requiring the use of wedges, torics and/or multiple decentered and tilted lenses.
The present invention provides a simple and inexpensive lens arrangement for overcoming these problems.